NASA FactsNational Aeronautics andSpace Administration

Lyndon B. Johnson Space Center IS-1997-06-ISS009JSCHouston, Texas 77058

International Space Station June 19971998

A History of U.S. Space Stations

Introduction

Space stations have long been seen as a laboratories forlearning about the effects of space conditions and as aspringboard to the Moon and Mars. In the United States,the Apollo lunar program preempted early station efforts inthe early 1960s, and changing priorities in the U.S.deferred post-Apollo station efforts to the 1980s. Since1984, space station design has evolved in response tobudgetary, programmatic, and political pressures,becoming increasingly international in the process. Thisevolution has culminated in the International SpaceStation, orbital assembly of which will begin in 1998.

The Beginning (1869-1957)

The concept of a staffed outpost in Earth orbit dates fromjust after the Civil War. In 1869, American writer Edward

Everett Hale published a science fiction tale called “TheBrick Moon” in the Atlantic Monthly. Hale’s mannedsatellite was a navigational aid for ships at sea. Haleproved prophetic. The fictional designers of the BrickMoon encountered many of the same problems withredesigns and funding that NASA would with its stationmore than a century later.

In 1923, Hermann Oberth, a Romanian, coined the term“space station.” Oberth’s station was the starting point forflights to the Moon and Mars. Herman Noordung, anAustrian, published the first space station blueprint in1928. Like today’s International Space Station, it hadmodules with different functions. Both men wrote thatspace station parts would be launched into space byrockets.

In 1926, American Robert Goddard made a majorbreakthrough by launching the first liquid-fueled rocket,setting the stage for the large, powerful rockets needed to

The first U.S. space station, Skylab, seen as its final mission approached in 1974

launch space station parts into orbit. Rocketry advancedrapidly during World War II, especially in Germany,where the ideas of Oberth and Noordung had greatinfluence. The German V-2 rocket, a missile with a rangeof about 300 miles, became a prototype for both U.S. andRussian rockets after the war.

In 1945, renowned German rocket engineer Wernhervon Braun came to the U.S. to build rockets for the U.S.Army. In the 1950s, he worked with Collier’s magazineand Walt Disney Studios to produce articles anddocumentaries on spaceflight. In them, he described awheel-shaped space station reached by reusable wingedspacecraft. Von Braun saw the station as an Earth-observation post, a laboratory, an observatory, and aspringboard for Moon and Mars flights.

On October 4, 1957, the Soviets launched Sputnik 1.This triggered the Cold War competition between the U.S.and Soviet Union in space which characterized the earlyyears of the Space Age—competition replaced today bycooperation in the International Space Station Program. Inresponse to Sputnik, the U.S. established the NationalAeronautics and Space Administration in 1958 and startedits first man-in-space program, Project Mercury, in 1959.

Apollo and Space Stations (1958-1973)

Project Mercury had hardly begun when NASA and theCongress looked beyond it, to space stations and apermanent human presence in space. Space stations wereseen as the next step after humans reached orbit. In 1959,A NASA committee recommended that a space station beestablished before a trip to the Moon, and the U.S. Houseof Representatives Space Committee declared a spacestation a logical follow-on to Project Mercury.

In April 1961, the Soviet Union launched the firsthuman, Yuri Gagarin, into space in the Vostok 1spacecraft. President John F. Kennedy reviewed manyoptions for a response to prove that the U.S. would notyield space to the Soviet Union, including a space station,but a man on the Moon won out. Getting to the Moonrequired so much work that the U.S. and Soviet Unionwere starting the race about even. In addition, the Moonlanding was an unequivocal achievement, while a spacestation could take many different forms.

Space station studies continued within NASA and theaerospace industry, aided by the heightened interest inspaceflight attending Apollo. In 1964, seeds were plantedfor Skylab, a post-Apollo first-generation space station.Wernher von Braun, who became the first director ofNASA’s Marshall Space Flight Center, was instrumentalin Skylab’s development.

By 1968, a space station was NASA’s leading candidatefor a post-Apollo goal. In 1969, the year Apollo 11 landedon the Moon, the agency proposed a 100-person permanentspace station, with assembly completion scheduled for1975. The station, called Space Base, was to be a

laboratory for scientific and industrial experiments. SpaceBase was envisioned as home port for nuclear-poweredtugs designed to carry people and supplies to an outpost onthe Moon.

NASA realized that the cost of shipping supplies to aspace station using expendable rockets would quicklyexceed the station’s construction cost. The agency alsoforesaw the need to be able to return things from a spacestation. A reusable spacecraft was the obvious solution. In1968, NASA first called such a spacecraft a space shuttle.

Skylab (1973-1974)

In May 1973, the U.S. launched the Skylab space stationatop a Saturn V rocket similar to those that took astronautsto the Moon. The rocket’s third stage was modified tobecome an orbital workshop and living quarters for three-person crews. Non-reusable Apollo spacecraft originallydesigned for Moon missions ferried astronauts to and fromthe station. Skylab hosted three different crews for stays of28, 56, and 84 days. Skylab astronauts conducted medicaltests and studied microgravity’s influence on fluid andmaterial properties. The crews also made astronomical,solar, and Earth observations. Long-duration microgravityresearch begun on Skylab will continue and be refined onthe International Space Station.

Skylab proved that humans could live and work in spacefor extended periods. The station also demonstrated theimportance of human involvement in construction andupkeep of orbital assets–the first Skylab crew performedemergency spacewalks to free a solar array jammed duringthe station’s launch.

Skylab was not designed for resupply, refueling, orindependent reboost. When the last Skylab crew headedhome in February 1974, NASA proposed sending theSpace Shuttle to boost Skylab to a higher orbit or even torefurbish and reuse the station. But greater than expectedsolar activity expanded Earth’s atmosphere, hasteningSkylab’s fall from orbit, and shuttle development fellbehind schedule. Skylab reentered Earth’s atmosphere in1979.

NASA Responds to Changing Priorities(1974-1979)

The Space Shuttle was originally conceived as a vehiclefor hauling people and things back and forth betweenEarth and a space station. People and the supplies theyneeded for a long stay in space would go up, and peopleand the industrial products and experiment samples theymade on the station would come down. But economic,political, social, and cultural priorities in the U.S. shiftedduring the Apollo era. Despite Apollo’s success, NASA’sannual budgets suffered dramatic cuts beginning in themid-1960s. Because of this, NASA deferred plans for apermanent space station until after the space shuttle was

flying, and explored international cooperative spaceprojects as a means of filling in for a permanent station.

The U.S. invited Europe to participate in its post-Apolloprograms in 1969. In August 1973, Europe formallyagreed to supply NASA with Spacelab modules, mini-laboratories that ride in the space shuttle’s payload bay.Spacelab provides experiment facilities to researchers frommany countries for nearly three weeks at a time–an interimspace station capability. Spacelab 1 reached orbit in 1983,on the ninth space shuttle flight (STS-9). The mainEuropean contributions to International Space Station, alaboratory module and a supply module, are based onSpacelab experience and technology.

U.S. and Soviet negotiators discussed the possibility of aU.S. Space Shuttle docking with a Soviet Salyut spacestation. This was an outgrowth of the last major U.S.-Russian joint space project, Apollo-Soyuz, the firstinternational spacecraft docking in 1975. The SpaceShuttle’s ability to haul things down from spacecomplimented Salyut’s ability to produce experimentsamples and industrial products–things one would want toreturn to Earth. NASA offered the Space Shuttle forcarrying crews and cargo to and from Salyut stations andin return hoped to conduct long-term research on theSalyuts until it could build its own station, but these effortsended with the collapse of U.S.-Soviet detente in 1979.

Defining the Goal and Building Support(1979-1984)

By 1979, development of the Space Shuttle was welladvanced. NASA and contractor engineers beganconceptual studies of a space station that could be carriedinto orbit in pieces by the Space Shuttle. The SpaceOperations Center was designed to serve as a laboratory, asatellite servicing center, and a construction site for largespace structures. The Space Operations Center studieshelped define NASA expectations for a space station.

The Space Shuttle flew for the first time in April 1981,and once again a space station was heralded as the nextlogical step for the U.S. in space. NASA founded theSpace Station Task Force in May 1982, which proposedinternational participation in the station’s development,construction, and operations. In 1983, NASA held the firstworkshop for potential space station users.

NASA Gets the Go-Ahead (1984-92)

These efforts culminated in January 1984, whenPresident Ronald Reagan called for a space station in hisState of the Union address. He said that the space stationprogram was to include participation by U.S. allies.

With the presidential mandate in place, NASA set up theSpace Station Program Office in April 1984, and issued aRequest for Proposal to U.S. industry in September 1984.In April 1985, NASA let contracts on four work packages,

each involving a different mix of contractors and managedby a separate NASA field center. (This was consolidatedinto three work packages in 1991.)

This marked the start of Space Station Phase Bdevelopment, which aimed at defining the station’s shape.By March 1986, the baseline design was the dual keel, arectangular framework with a truss across the middle forholding the station’s living and working modules and solararrays.

By the spring of 1985, Japan, Canada, and the EuropeanSpace Agency each signed a bilateral memorandum ofunderstanding with the U.S. for participation in the spacestation project. In May 1985, NASA held the first spacestation international user workshop in Copenhagen,Denmark. By mid-1986, the partners reached agreementon their respective hardware contributions. Canada wouldbuild a remote manipulator system similar to the one it hadbuilt for the space shuttle, while Japan and Europe wouldeach contribute laboratory modules. Formal agreementswere signed in September 1988. These partners’contributions remain generally unchanged for theInternational Space Station.

In 1987, the dual keel configuration was revised to takeinto account a reduced space shuttle flight rate in the wakeof the Challenger accident. The revised baseline had asingle truss with the built-in option to upgrade to the dualkeel design. The need for a space station lifeboat–calledthe assured crew return vehicle–was also identified.

In 1988, Reagan gave the station a name–Freedom.Space Station Freedom’s design underwent modificationswith each annual budget cycle as Congress called for itscost to be reduced. The truss was shortened and the U.S.Habitation and Laboratory modules reduced in size. Thetruss was to be launched in sections with subsystemsalready in place. Despite the redesigns, NASA andcontractors produced a substantial amount of hardware. In1992, in moves presaging the current increasedcooperation between the U.S. and Russia, the U.S. agreedto buy Russian Soyuz vehicles to serve as Freedom’slifeboats (these are now known as Soyuz crew transfervehicles) and the Shuttle-Mir Program got its start.

International Space Station (1993-2012)

In 1993, President William Clinton called for the stationto be redesigned once again to reduce costs and includemore international involvement. To stimulate innovation,teams from different NASA centers competed to developthree distinct station redesign options. The White Houseselected the option dubbed Alpha.

In its new form, the station uses 75 percent of thehardware designs originally intended for the Freedomprogram. After the Russians agreed to supply majorhardware elements, many originally intended for their Mir2 space station program, the station became known as theInternational Space Station. Russian participation reduces

the station’s cost to the U.S. while permitting expansion tobasic operational capability much earlier than Freedom.This provides new opportunities to all the station partnersby permitting early scientific research.

The program’s management was also redesigned.Johnson Space Center became lead center for the spacestation program, and Boeing became prime contractor.NASA and Boeing teams are housed together at JSC toincrease efficiency through improved communications.

The first phase of the International Space StationProgram, the Shuttle-Mir Program, kicked off in February1994 with STS-60, when Sergei Krikalev became the firstRussian astronaut to fly on a shuttle. The Shuttle-MirProgram is giving U.S. astronauts their first long-durationspace experience since Skylab. The Shuttle-Mir Programalso gives U.S. and Russian engineers and astronautsexperience in working together. Space station hardware isbeing tested and improved. For example, difficulties withMir’s cooling system led to modifications in theInternational Space Station design.

The Shuttle-Mir Program continued in February 1995,when Discovery rendezvoused with Mir during the STS-63mission with cosmonaut Vladimir Titov aboard. In March1995, U.S. astronaut Dr. Norman Thagard lifted off in theRussian Soyuz-TM 21 spacecraft with two Russiancosmonauts for a three-month stay on Mir. In June 1995,on the STS-71 mission, the Shuttle Atlantis docked withthe Mir station for the first time and picked up Thagardand his colleagues, plus experiment samples and otheritems from the station, for return to Earth.

In November 1995, on mission STS-74, Atlantisdelivered the Russian-built Docking Module to Mir - the

first time a shuttle added a module to a space station, a taskwhich will be commonplace during assembly of theInternational Space Station.

On STS-76 in March 1996, Atlantis dropped off U.S.astronaut Shannon Lucid for 6 months of scientificresearch on Mir, the first time a shuttle delivered a long-duration crew member to a space station. Astronauts LindaGodwin and Richard Clifford performed a spacewalkoutside Mir, the first time American astronauts performeda spacewalk outside a space station since the Skylabmissions.

In August 1996, on the STS-79 mission, Atlantis dockedwith Mir and exchanged Lucid for John Blaha. Crewexchange will also be commonplace during operations onthe International Space Station. All shuttle missions to Mirdeliver supplies, equipment, and water, and return to Earthexperiment results and equipment no longer needed. Blahareturned to Earth aboard Atlantis on STS-81, which leftbehind Jerry Linenger. He returned to Earth on STS-84,which left behind Michael Foale.

Assembly of the International Space Station begins inJune 1998 with launch of the FGB propulsion module. Thefirst International Space Station crew−William Shepherd,Sergei Krikalev, and Yuri Gidzenko−will arrive in January1999, starting a permanent human presence aboard thenew station. The station’s first laboratory module, suppliedby the U.S., will reach the International Space Station inMay 1999. After the Lab is in place, assembly flights willbe interspersed with flights dedicated to research.International Space Station operations are planned tocontinue until at least 2013.

The International SpaceStation is shown herewith assembly completedin early 2003. Thenew station is the largestand most complexpeacetime internationalcollaboration everundertaken. It also willbe the largest spacecraft ever built.

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International Space Station National Aeronautics and Space Administration

International Space Station

The International Space Station Program is Underway Introduction

The International Space Station has three phases,

each designed to maximize joint space experience and permit early utilization and return on our investment. In Phase I, Americans and Russians will work together in laboratories on Mir and the shuttle. They will conduct joint spacewalks and practice space station assembly by adding new modules to Mir. American astronauts .will live and work on Mir for months beside their .Russian counterparts, amassing the first U.S. long-duration space experience since Skylab (1973- 1974).

International Space Station Phase I began with Russian cosmonaut Sergei Krikalev's flight aboard the Space Shuttle Discovery in February 1994 on STS-60. In February 1995, on the STS-63 mission. Discovery flew around the Russian Mir space station with Vladimir Titov on board as a mission specialist. During the fly around. Discovery stopped 37 feet from Mir-a rehearsal for the first docking between Space Shuttle Atlantis and Mir in May or June 1995. In March 1995, U.S. astronaut Dr. Norman Thagard flew to Mir for a three-month stay with two Russian cosmonauts. Phase I Impact on Phases II and III

The goal of Phase I is to lay the groundwork for International Space Station Phases II and III. Phase n will place in orbit a core space station with a U.S. Laboratory module, the first dedicated laboratory on the station. The U.S. Laboratory will be put to work

during utilization flights in Phase in, while assembly continues. Phase in ends when assembly is complete (scheduled for mid-2002) and astronauts and cosmonauts from many countries commence a planned 15 years of research on the International Space Station.

Phase I is contributing to the success of Phases II and III in four major areas: • Operations-learning to work together on the ground

and in space • Risk reduction-mitigation of potential surprises in

hardware exchange, working methods, spacecraft environment, and spacewalks

• Long-duration stays on a space station-amassing experience

• Science-early initiation of science and technology research

Space Station Mir-Shuttle's Partner in Phase I

Mir represents a unique capability-an operational long- term space station which can be permanently staffed by two or three cosmonauts. Visiting crews have raised Mir's population to six for up to a month.

Mir is the first space station designed for expansion. The 20.4-ton core module, Mir's first building block, was launched in February 1986. The core module provides basic services (living quarters, life support, power) and scientific research capabilities. Soyuz-TM manned transports and automated Progress-M supply ships dock at two axial docking ports, fore and aft.

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Expansion modules dock first at the forward port then transfer to one of four radial berthing ports using a robot arm (except for the expansion module, Kvant-see below).

Up to 1990, the Russians added three expansion modules to the Mir core: • Kvant. Berthed at the core module's aft axial port in

1987, the module weighs 11 tons and carries telescopes and equipment for attitude control and life support. Kvant blocked the core module's aft port, but had its own aft port which took over as the station's aft port.

• Kvant 2. Berthed at a radial port in 1989, the module weighs 19.6 tons and carries an EVA airlock, two solar arrays, and science and life support equipment.

• Kristall. Berthed opposite Kvant 2 in 1990, Kristall weighs 19.6 tons and carries two stowable solar arrays, science and technology equipment, and a docking port equipped with a special androgynous docking mechanism designed to receive heavy (up to about 100 tons) spacecraft equipped with the same kind of docking unit. The androgynous unit was originally developed for the Russian Buran shuttle program. The Russians will move Kristall to a different radial Mir port to make room for the new Spektr module in May 1995. Atlantis will use the androgynous docking unit on Kristall for the first shuttle-Mir docking in June 1995. Three more modules, all carrying U.S. equipment,

will be added to Mir in 1995 for International Space Station Phase I:

• Spektr. Launch on a Russian Proton rocket from the

Baikonur launch center in central Asia is currently set for May 1995. The module will be berthed at the radial port opposite Kvant 2 after Kristall is moved out of the way. Spektr will transport four solar arrays and scientific equipment (including more than 1600 Ibs of U.S. equipment).

• Docking Module. The module will be launched in the payload bay of Atlantis and berthed at Kristall's androgynous docking port during STS-74 in October 1995. The docking module makes shuttle dockings with Mir easier and will carry two solar arrays-one Russian and one jointly developed by the U.S. and Russia—to augment Mir's power supply.

• Priroda. Launch on a Russian Proton rocket is scheduled for November 1995. Priroda will berth at the radial port opposite Kristall and will carry microgravity research and Earth observation equipment (including 2200 Ib of U.S. equipment).

In late 1995, after Priroda is added, Mir will mass

more than 100 tons. The station will be made up of seven modules launched separately and brought together in space over ten years. Experience gained by Russia during Mir assembly provides valuable experience for International Space Station assembly in Phases II and III. Phase I Shuttle Mission Summaries

STS-60 (February 3-11. 1994) This mission inaugurated International Space

Station Phase I. Veteran Russian cosmonaut Sergei Krikalev served as a mission specialist aboard Discovery. He conducted experiments beside his American colleagues in a Spacehab laboratory module carried in Discovery's payload bay.

STS-63 (February 3-11. 1995) Discovery maneuvered around Mir and stopped 37

feet from the Kristall module's special androgynous docking unit, which Atlantis will use to dock with Mir on the STS-71 mission. Cosmonauts on Mir and Discovery's crew-which included veteran Russian cosmonaut Vladimir Titov- beamed TV images of each other's craft to Earth. For a time it appeared that minor thruster leaks on Discovery might keep the two craft at a preplanned contingency rendezvous distance of 400 feet. However, mission control teams and management in Kaliningrad and Houston worked together to determine that the leaks posed no threat to Mir, so the close rendezvous went ahead. The minor problem became a major builder of confidence and joint problem- solving experience for later International Space Station phases. Titov served on board Discovery as a mission specialist, performing experiments beside his American colleagues in a Spacehab module in the orbiter's payload bay.

STS-71 (May-June 1995) Atlantis will be launched carrying five astronauts,

two Russian cosmonauts, and, in its payload bay, a Spacelab module and an orbiter docking system for docking with Mir. The STS-71 orbiter docking system is designed for use on this mission only-subsequent shuttle-Aft'r docking missions will use a Muldmir orbiter docking system. The STS-71 and Multimir orbiter docking systems are outwardly identical-they consist of a cylindrical airlock with a Russian-built

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androgynous docking mechanism on top. For ST^-71, Atlantis will dock with an identical androgynous unit on Mir's Kristall module. The shuttle will be used for the first time to change a space station crew, a task which will become a routine part of its duties in later International Space Station phases. Atlantis will .drop off cosmonauts Anatoli Solovyev and Nikolai Budarin, and pick up Vladimir Dezhurov, Gennadi Strekalov, and U.S. astronaut Norman Thagard for return to Earth. They were launched from Russia in the Soyuz-TM 21 spacecraft on March 14. Thagard and his Russian colleagues will be completing a three-month stay on Mir, the first long-duration space mission involving an American since the last U.S. Sky lab mission in 1974. The joint crew will carry out experiments similar to those planned for International Space Station Phases n and III. Atlantis will remain docked to Mir for five days.

STS-74 (October-November 1995) Atlantis will carry the Russian-built docking

module, which has androgynous docking mechanisms at top and bottom. During flight to Mir, the crew will use the orbiter's remote manipulator system robot arm to hoist the docking module from the payload bay and position its bottom androgynous unit atop Atlantis' orbiter docking system. Atlantis will then dock to Kristall using the docking module's top androgynous unit. After three days, Atlantis will undock from the docking module's bottom androgynous unit and leave the docking module permanently docked to Kristall, where it will improve clearance between the shuttle and Mir's solar arrays during subsequent dockings. The docking module also carries two solar arrays, one Russian and one U.S.-Russian, which will increase power available on Mir for experiments. No crew exchange is scheduled, but on board Mir will be an astronaut from the European Space Agency (ESA), halfway through a four-month stay on the station, and on board Atlantis will be a Canadian astronaut. The European long- duration mission is part of the Euromir space research program, which included a month-long stay on Mir by ESA astronaut Ulf Merbold in 1994. Canada built the shuttle's robot arm and will provide robotics systems for the International Space Station in Phase II, while Europe will provide a laboratory module for the station in Phase III. On this and subsequent flights Atlantis will deliver water, supplies, and equipment to Mir and will return to Earth experiment samples, dysfunctional equipment for analysis, and products manufactured on the station.

STS-76 (March-April 1996) Atlantis will deliver astronaut Shannon Lucid to

Mir for a five-month stay. The orbiter will carry a single Spacehab module in its payload bay, and will remain docked to the Russian station for five days. While docked, astronauts Linda Godwin and Michael R. "Rich" Clifford will perform a spacewalk to transfer three experiments from Atlantis to Mir's exterior and evaluate International Space Station hardware.

STS-79 (August 1996) Astronaut Shannon Lucid, delivered to Mir on STS-

76, will be picked up and astronaut Jerry Linenger will be dropped off for a planned four-month stay on the Russian station. U.S. astronauts will perform a spacewalk during the five-day docked phase. Atlantis will carry a Spacehab double module.

STS-81 (December 1996) Astronaut Jerry Linenger, delivered on STS-79, will

be returned to Earth and astronaut John Blaha will take up residence on Mir for four months. Atlantis will also deliver U.S. and Russian equipment for spacewalks to take place on this and subsequent missions. Two Russians or an American and a Russian will perform U.S. experiments as part of a spacewalk during or after the five-day docked phase. Atlantis will carry a Spacehab double module.

STS-84 (May 1997) Astronaut John Blaha, delivered on STS-81, will be

picked up and astronaut Scott Parazynski dropped off for a four-month stay on Mir. Atlantis will carry a Spacehab double module, and will remain docked to Mir for five days.

STS-86 (September 1997) Atlantis will pick up astronaut Scott Parazynski,

dropped off on STS-84, and will deliver a joint U.S.-Russian solar dynamic energy module. As many as two spacewalks by U.S. astronauts and Russian cosmonauts will be needed to deploy the energy module outside Mir. The solar dynamic system will heat a working fluid which will drive a turbine, generating more electricity than current photovoltaic solar arrays. The Mir solar dynamic energy module will test the system for possible use on the International Space Station. In addition, developing the solar dynamic energy module will provide joint engineering experience. The astronauts and cosmonauts will also retrieve and deploy experiments outside Mir.

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International Space Station

Phase I-III Overview Introduction

The International Space Station program has three phases. Each builds from the last, and each is made up of milestones representing new capabilities. Phase I (1994-1997) uses existing assets-primarily U.S. shuttle orbiters and the Russian space station Mir-to build joint space experience and start joint scientific research. In Phase II (1997-1999), the core International Space Station will be assembled from U.S. and Russian parts and early scientific research on

the station will begin. Phase III (1999-2002) includes utilization flights, during which crews of docked shuttle orbiters will conduct research inside the station's U.S. Laboratory module. Also during this phase European, Japanese, Russian, Canadian, and U.S. components will be added to expand the station's capabilities. Phase III ends in June 2002, when International Space Station assembly is completed and a planned 10 years of operations by international crews commence.

International Space Station Phase I: Shuttle and Mir (1994-1997) PhaseI Shuttle Missions STS-60 February 3-11,1994 Discovery First Phase I flight STS-63 February 3-11.1995 Discovery Mir rendezvous STS-71 June 1995 Atlantis First Mir docking; pick up U.S. astronaut and 2 cosmonauts STS-74 November 1995 Atlantis Docking module added to Mir STS-76 April 1996 Atlantis Shuttle drops off U.S. astronaut at Mir STS-79 August 1996 Atlantis U.S. astronaut picked up; leave replacement STS-81 December 1996 Atlantis U.S. astronaut picked up; leave replacement STS-84 May 1997 Atlantis U.S. astronaut picked up; leave replacement STS-86 September 1997 Atlantis U.S. astronaut picked up; solar dynamic turbine energy module added to Mir

International Space Station Phase I serves as a 3-year prologue to station assembly in Phases n and ni. Phase I began on February 3,1994, when veteran cosmonaut Sergei Krikalev became the first Russian to fly on a U.S. spacecraft. On the STS-60 mission, Krikalev worked beside his U.S. crewmates in a Spacehab module in Discovery's payload bay, helping pave the way for future joint research.

The STS-63 mission built on STS-60 experience. On February 6,1995, Discovery rendezvoused with the Mir space station in rehearsal for shuttle-Mir dockings. For a time it seemed that minor leaks in Discovery's thrusters would keep shuttle and station at a preplanned contingency rendezvous distance of 400 feet. Mission control teams in Houston and Kaliningrad worked together to determine that the leaks posed no threat to Mir. The minor problem

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became a major builder of confidence and joint problem- solving experience for later International Space Station phases. The planned close rendezvous went ahead, with Discovery stopping 37 feet from the station. On board Discovery, cosmonaut Vladimir Titov conducted scientific research in a Spacehab module with his U.S. crewmates.

On STS-71 (June 1995) Space Shuttle Atlantis will dock with Mir for the first time. Atlantis and Mir will be linked on this and all subsequent docking missions by the orbiter docking system, which comprises a Russian docking mechanism atop a U.S. pressurized tunnel mounted in the orbiter's payload bay. The crews will conduct joint research on Mir and in a Spacelab module on Atlantis. In addition, for the first time the orbiter will be used to change a space station crew, a task which will become a routine part of its astronauts will work in the U.S. laboratory module for more than two weeks at a time while a docked shuttle orbiter provides assured Earth return capability. Utilization flights are designed to start U.S. research on the International Space Station as early as possible.

The first assembly milestone takes place on the next U.S. flight, STS-97. Endeavour's crew will berth an airlock module on Resource Node 1. The airlock will permit U.S. astronauts and Russian cosmonauts to perform routine spacewalks when the shuttle orbiter is not present (contingency spacewalks are possible as early as three- person permanent human presence capability-April 1998- by using hatches on the Russian service module). Addition of the airlock makes easier the limited number of spacewalks required to assemble the International Space Station.

Addition of new international laboratories constitutes most of the rest of the Phase III assembly milestones. The first Russian research module, similar to the science modules on the Mir space station, will be added in August 1999. Russian research modules will also be added in June 2000 and May 2001. The Japanese experiment module (JEM) and Europe's attached pressurized module will be added over the course of five assembly flights in 2000-2001. Robotic equipment inside the European laboratory will aid human experimenters, lessening demands on their time. The JEM laboratory has a special "front porch" for exposing experiments and equipment to space conditions. Europe plans to launch the attached pressurized module on its Ariane 5 rocket, while Japan is considering using its H-n rocket to launch portions of the JEM.

The U.S. will add the centrifuge module on STS-116 in October 2001. The centrifuge will for the first time permit studying the effects of sustained partial gravity on living things. For example, the centrifuge will be able to simulate a stay on the surface of Mars, where the gravitational pull is only one-third as strong as on Earth.

The largest single element of the International Space Station, the truss, grows segment by segment during Phase III, with the tenth and last segment added during the 15th U.S. assembly flight, STS-117, in January 2002. The completed truss, measuring more than 350 feet in length, will hold systems requiring exposure to space, such as communications antennas; external cameras; mounts for external payloads; and equipment for temperature control, transport around the station's exterior during spacewalks, robotic servicing, and stabilization and attitude control.

The truss will also support eight Sun-tracking solar array pairs. Combined with the arrays on the Russian segment, they will provide the station with 110 kilowatts of electrical power-twice as much power for experiments as the old Freedom design and more than 10 times as much as Sky lab or Mir.

In February 2002, a second Soyuz crew transfer vehicle will dock, enabling six people to return to Earth when the shuttle orbiter is absent and signaling achievement of six- person permanent human presence capability. Later in the month, on the STS-119 mission, Atlantis will deliver the U.S. habitation module. Once outfitted, the habitation module will provide a crew of four with dining, personal hygiene, sleep, conference, and recreation facilities during their long stays in space.

Completion of U.S. habitation module outfitting in 2002 on Shuttle mission STS-121, the 16th U.S. assembly flight, signals the end of Phase m. International Space Station will be complete in 2002 and ready to provide unprecedented space research capability in the new millennium.

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International Space StationRussian Space Stations

Introduction

The International Space Station, which will be assembledbetween mid-1998 and 2003, will contain many Russianhardware elements developed in the nearly 30 years of theRussian space station program. The history of Russian spacestations is one of gradual development marked by upgradesof existing equipment, reapplication to new goals ofhardware designed for other purposes, rapid recovery fromfailures, and constant experimentation. The earliest Salyutstations were single modules, designed for only temporaryoperations. Mir, the most recent station, is a permanentfacility in orbit since 1986 with a base made up of fourseparately-launched modules. Additional modules have beenadded to now total six laboratory modules and one dockingmodule, added to allow the Space Shuttle to more easily dockwith the station. U.S. Space Shuttles have been periodicallydocking with the Mir since July 1995. U.S. astronauts havemaintained a permanent presence onboard Mir since March1996 and that presence is expected to continue through 1998.

Prelude to Space Stations (1903-1964)

In 1903, Russian schoolteacher Konstantin Tsiolkovskywrote Beyond the Planet Earth, a work of fiction based onsound science. In it, he described orbiting space stationswhere humans would learn to live in space. Tsiolkovskybelieved these would lead to self-contained space settlementsand expeditions to the Moon, Mars, and the asteroids.Tsiolkovsky wrote about rocketry and space travel until hisdeath in 1935, inspiring generations of Russian spaceengineers.

Soviet engineers began work on large rockets in the 1930s.In May 1955, work began on the Baikonur launch site incentral Asia. In August 1957, the world’s firstintercontinental ballistic missile lifted off from Baikonur on atest flight, followed by the launch of Sputnik 1, world’s firstartificial satellite, on October 4, 1957. OnApril 12, 1961, Yuri Gagarin lifted off from Baikonur in theVostok 1 capsule, becoming the first human in space.

A year later, Soviet engineers described a space stationcomprised of modules launched separately and broughttogether in orbit. A quarter-century later, in 1987, thisconcept became reality when the Kvant module was added tothe Mir core station.

First-Generation Stations (1964-1977)

First-Generation StationsSalyut 1 civilian 1971 First space stationUnnamed civilian 1972 FailureSalyut 2 military 1973 First Almaz station; failureCosmos 557 civilian 1973 FailureSalyut 3 military 1974-75 Almaz stationSalyut 4 civilian 1974-77Salyut 5 military 1976-77 Last Almaz station

First-generation space stations had one docking port andcould not be resupplied or refueled. The stations werelaunched unmanned and later occupied by crews. There weretwo types: Almaz military stations and Salyut civilianstations. To confuse Western observers the Soviets calledboth kinds Salyut.

Salyut 1 station with Soyuz about to dock

The Almaz military station program was the first approved.When proposed in 1964, it had three parts: the Almazmilitary surveillance space station, Transport LogisticsSpacecraft for delivering soldier-cosmonauts and cargo, andProton rockets for launching both. All of these spacecraftwere built, but none was used as originally planned.

Soviet engineers completed several Almaz station hulls by1970. The Soviet leadership ordered Almaz hulls transferredto a crash program to launch a civilian space station. Workon the Transport Logistics Spacecraft was deferred, and theSoyuz spacecraft originally built for the Soviet manned Moonprogram was reapplied to ferry crews to space stations.Salyut 1, the first space station in history, reached orbitunmanned atop a Proton rocket on April 19, 1971.

The early first-generation stations were plagued byfailures. The crew of Soyuz 10, the first spacecraft sent toSalyut 1, was unable to enter the station because of a dockingmechanism problem. The Soyuz 11 crew lived aboard Salyut1 for three weeks, but died during return to Earth because theair escaped from their Soyuz spacecraft. Then, three first-generation stations failed to reach orbit or broke up in orbitbefore crews could reach them. The second failed stationwas Salyut 2, the first Almaz military station to fly.

The Soviets recovered rapidly from these failures. Salyut3, Salyut 4, and Salyut 5 supported a total of five crews. Inaddition to military surveillance and scientific and industrialexperiments, the cosmonauts performed engineering tests tohelp develop the second-generation space stations.

Second-Generation Stations (1977-1985)

Second-Generation StationsSalyut 6 civilian 1977-82Salyut 7 civilian 1982-91 Last staffed in 1986

With the second-generation stations, the Soviet spacestation program evolved from short-duration to long-durationstays. Like the first-generation stations, they were launchedunmanned and their crews arrived later in Soyuz spacecraft.Second-generation stations had two docking ports. Thispermitted refueling and resupply by automated Progressfreighters derived from Soyuz. Progress dockedautomatically at the aft port, and was then opened andunloaded by cosmonauts on the station. Transfer of fuel tothe station took place automatically under supervision fromthe ground.

A second docking port also meant long-duration residentcrews could receive visitors. Visiting crews often includedcosmonaut-researchers from Soviet bloc countries orcountries sympathetic to the Soviet Union. Vladimir Remekof Czechoslovakia, the first space traveler not from the U.S.or the Soviet Union, visited Salyut 6 in 1978.

Visiting crews relieved the monotony of a long stay inspace. They often traded their Soyuz spacecraft for the onealready docked at the station because Soyuz had only alimited lifetime in orbit. Lifetime was gradually extendedfrom 60-90 days for the Soyuz Ferry to more than 180 daysfor the Soyuz-TM.

Salyut 6 Key Facts• The station received 16 cosmonaut crews, including six

long-duration crews. The longest stay time for a Salyut6 crew was 185 days. The first Salyut 6 long-durationcrew stayed in orbit for 96 days, beating the 84-dayworld record for space endurance established in 1974 bythe last Skylab crew.

• The station hosted cosmonauts from Hungary, Poland,Romania, Cuba, Mongolia, Vietnam, and East Germany.

• Twelve Progress freighters delivered more than 20 tonsof equipment, supplies, and fuel.

• An experimental transport logistics spacecraft calledCosmos 1267 docked with Salyut 6 in 1982. Thetransport logistics spacecraft was originally designed forthe Almaz program. Cosmos 1267 proved that largemodules could dock automatically with space stations, amajor step toward the multimodular Mir station and theInternational Space Station.

Salyut 7 Key Facts• Salyut 7, a near twin of Salyut 6, was home to 10

cosmonaut crews, including six long-duration crews.The longest stay time was 237 days.

• Cosmonauts from France and India worked aboard thestation, as did the first female space traveler since 1963.

• Thirteen Progress freighters delivered more than 25 tonsof equipment, supplies, and fuel to Salyut 7.

• Two experimental transport logistics spacecraft, Cosmos1443 and Cosmos 1686, docked with Salyut 7. Cosmos1686 was a transitional vehicle, a transport

Salyut 6: 1977-1982

logistics spacecraft redesigned to serve as an experimentalspace station module.

• Salyut 7 was abandoned in 1986 and reentered Earth’satmosphere over Argentina in 1991.

Third-Generation Station: Mir (1986-present)

Third-Generation StationMir civilian 1986-present First permanent station

Mir is the first permanent space station. The station hasbeen in orbit for 11 years, and staffed continuously for thepast 7 years. The complex presently weighs more than 100

tons, and consists of the Mir core, Kvant, Kvant 2, Kristall,Spektr, Priroda and Docking modules. Mir measures morethan 107 feet long with docked Progress-M and Soyuz-TMspacecraft, and is about 90 feet wide across its modules.

Mir Module Descriptions• The Mir core resembles Salyut 7, but has six ports

instead of two. Fore and aft ports are used primarily fordocking. Four radial ports in a node at the station’s frontare for berthing large modules. The core weighed 20.4tons at launch in 1986.

• Kvant was added to the Mir core’s aft port in 1987. Thissmall, 11-ton module contains astrophysics instrumentsand life support and attitude control equipment.

• Kvant 2, added in 1989, carries an EVA airlock, solararrays, and life support equipment. The 19.6-ton moduleis based on the transport logistics spacecraft originallyintended for the Almaz military space station program ofthe early 1970s.

• Kristall, added in 1990, carries scientific equipment,retractable solar arrays, and a docking node equippedwith a special androgynous docking mechanism designedto receive spacecraft weighing up to 100 tons.Originally, the Russian Buran shuttle, which made oneunmanned orbital test flight in 1988, would have dockedwith Mir using the androgynous unit. Space ShuttleAtlantis used the androgynous unit to dock with Mir forthe first time on the STS-71 mission in July 1995. OnSTS-74, in November 1995, Atlantis permanentlyattached a Docking Module to Kristall’s androgynousdocking unit. The Docking Module improved clearancebetween Atlantis and Mir’s solar arrays on subsequentdocking flights. The 19.6-ton Kristall module is basedon the transport logistics spacecraft originally designed

Salyut 7 with Cosmos 1686 attached

Mir Space Station, 1989, with Base Block, center; Kvant module, right; and Kvant-2 module, top

to carrySoviet soldier-cosmonauts to the Almaz military space

stations.• Spektr was launched on a Russian Proton rocket from the

Baikonur launch center in central Asia on May 20, 1995.The module was berthed at the radial port oppositeKvant 2 after Kristall was moved out of the way. Spektrcarries four solar arrays and scientific equipment,including more than 1600 pounds of U.S. equipment.The focus of scientific study for this module is Earthobservation, specifically natural resources andatmosphere. The equipment onboard is supplied by bothRussia and the United States.

• Priroda was the last science module to be added to theMir, launched from Baikonur on April 23, 1996, itdocked to the space station as scheduled on April 26. Itsprimary purpose is to add Earth remote sensingcapability to Mir. It also contains the hardware andsupplies for several joint U.S.-Russian scienceexperiments.

• The Docking Module was delivered and installed byshuttle mission STS-74 in November 1995, making itpossible for the space shuttle to more easily dock withMir. On STS-71 in June 1995, the shuttle docked withthe Kristall module on Mir. However, to make thatdocking possible, the Kristall configuration had to bechanged to give the shuttle enough clearance to dock.Russian cosmonauts performed a spacewalk to movetheKristall module from a radial axis to a longitudinal axis,relative to Mir. After the shuttle departed, Kristall wasmoved back to its original location.

Modules for Mir’s radial berthing ports first dock at thefront port. Each module carries a manipulator arm whichlocks into a socket on Mir. The arm pivots the module intoplace at the proper radial port

Mir Key Facts• An important goal of the Mir program has been to

maintain a permanent human space presence. Except or

two brief periods (July 1986-February 1987; April- September 1989), Russian cosmonauts have lived aboard

Mir continuously for the past 9 years, demonstratingproven experience in space station operations.

• Dr. Valeri Polyakov arrived on Mir on Soyuz-TM 18 inJanuary 1994 and returned to Earth on Soyuz-TM 20 onMarch 21, 1995. He lived in orbit for more than 438days, a new world record.

• Through 1994, 16 long-duration crews lived and workedon Mir. In all, 19 piloted craft have docked with thestation.

• Cosmonaut-researchers from Afghanistan, Austria,Britain, Bulgaria, the European Space Agency, France,Germany, Japan, Kazakhstan, and Syria have visitedMir. European and French cosmonauts lived on Mir foras long as a month. U.S. astronauts typically spend fourmonths on the station, although U.S. astronaut ShannonLucid has had the longest tour onboard, six months in1996.

• More than 40 Progress and Progress-M freighters havedelivered more than 100 tons of supplies and fuel to Mir.The improved Progress-M occasionally carries a capsulefor returning to Earth a small quantity of experimentresults and industrial products from the station.Occasionally cargo comes back to Earth withcosmonauts in Soyuz-TM capsules. Beginning with STS-71, the shuttle has returned to Earth more industrialproducts and experiment samples than is possible usingthe Progress-M capsules or Soyuz-TM. In addition, theshuttle can be used to return components from Mir’sexterior, such as solar arrays, for studying the effects oflong exposure to space conditions–a capability notavailable with Progress-M and Soyuz-TM. Importantlessons from Mir operations and Shuttle-Mir operationsand research are being incorporated into the InternationalSpace Station design and planning.